Math! She’s a fickle mistress. She takes without asking. In this case, however, she gives without expectation. If you purchased the $100 Nokia Lumia 900 Windows Phone from AT&T – a phone our own Jared Newman called “a solid slab” and other niceties – Nokia would like to put $100 toward your AT&T bill for the trouble.

[S]oon after this flagship device began selling, we identified a software issue. In short, a memory management issue was discovered that could, in some cases, lead to loss of data connectivity. This issue is purely in the phone software, and is not related to either phone hardware or the network itself. As a proactive and prudent measure, we decided to take immediate action. We have identified the issue, and have developed a solution.

If you have already purchased a Lumia 900, we are making two options available to you:

• You will be able to update your device with the latest software via Zune on or around Monday, April 16th.

or

• Swap your current Lumia 900 for an updated Lumia 900

We apologize for any inconvenience this may have caused. As a gesture of good will, every individual who has already purchased a Nokia Lumia 900 — or who will purchase one between now and April 21st – will receive a $100 credit to their AT&T bill from Nokia.

Get that? You can even cash in on this deal if you haven’t bought the phone yet. And the phone you buy will most likely have the updated software on it anyway. Win? Win.